Heater



FIG. 1 is a front perspective view of a heater showing my new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view, with the cord shown in an alternate position;

FIG. 4 is a left side elevation view thereof;

FIG. 5 is a right side elevation view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken line showing is included for the purpose of illustrating portions of the article and forms no part of the claimed design. 

The ornamental design for a heater, as shown and described. 